Electrical relay



2 Sheets-Sheet 1 B. E. OHAGAN ELECTRICAL RELAY Filed Feb. 2, 193].

INVENTOR. Z3.E,0Ha a.

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"July 14, 1931. OHAGAN 1,814,329

ELECTRICAL RELAY Filed Feb. 2, 1931 2 Sheets-Sheet 2 INVENTOR. Z3. E O 'He7an,

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the relay,

Patented July 14, 1931 UNITED STATES PATENT OFFICE BERNARD E. OHAQAN, 9F SWISBVALE, PENNSYLVANIA, ASSIGNOB TO THE UNION SWITCH & SIGJIAL GOMPAHY, 0F SWISSVALE, PENNSYLVANIA, A CORPORATION OF PENNSYLVANIA EL GTRIGAL RELAY My invention relates to electrical relays, and particularly to electrical relays of the alternating current type responsive to current of one frequency but not to current of another frequency,

I will describe one form of relay embodying my invention, and will then point out the novelfeatures thereof in claims.

In the accompanying drawings, Fig. 1 is a View, showing in front elevation, one form of relay embodying m. invention. Fig, 2 is a top plan view, and 3 is a right hand end View of the relay shown in Fig. 1, with the contact structure removed.

Similar reference characters refer to similar parts in all threeviews.

Referring to the drawings, the reference character 1 designates a base plate which supports the operating mechanism of the relay. Attached to the base plate 1 are two upstanding posts 2 and 3 provided with trunnion screws 4 and 5, respectively, and mounted for rotation in these trunnion screws is a shaft 6 carrying a vane 7 of suitable electroconductive material such as aluminum.

C p ating with the vane 7 e tw substantially U-shaped ma netizable cores 8 and 9 As best seen in igs. 2 and 3, these cores are secured to the base plate 1 on opposite sides of the vane by means of suitable supports, here shown as brackets 10, and are arranged with the pole pieces of one core confronting the pole eces of the other core but pole pieces of the other core by air gaps 11. These cores comprise a single magnetic circuit, and this magnetic circuit is energized by means of a winding 12 which I will term the local winding of This winding may be a single coil but, as here shown, it is constructed of two coils connected in series, one coil being located on each of the cores Sand 9.

.AlSO coo erating With the Vane 7 is a third magnetiza le core 13. This core is likewise substantially C-shaped, and the poles thereof are located on 0p vQsite sides of the vane a ljacent the poles o the coresfi and ,9. As here shown, the core 13 is mounted on non-magnetizable supports 14,, and is secured to .the base plate 1 by means of screws 15, which extend downwardly through the core and through the supports, and which are thread ed into the base plate 1. The core 13 is provided with an energizing winding 16 which I will term the control winding of the relay, and which for convenience, is made in two sections connected in series, one section be ing located on each side of the vane, as best seen in Fig. 2.

The portion of the relay mechanism thus far described is well known in the art and its operation is as follows. When the two windings 16 and 12 are supplied with alternating currents, the vane 7 is traversed by one magnetic flux, due to the flux which is set up in core 13 by the current in winding 16, and by two other magnetic fluxes due to the flux which is set up in cores 8 and 9 by the currentin winding 12. The fluxes due to winding 12 induce currents in the vane, and if these currents and the flux due to winding 16 have the proper phase relations, these currents will react with the flux due to winding 16 to produce a torque on the vane which tends to rotate it. The direction of the vane rotation thus produced depends upon the relative polarity of the currents in the two windings 12 and 16, and may be reversed by reversing the relative polarity of the current supplied to winding 16. For purposes of the present description, I will assume that when the current is supplied to winding 16, it will be of such polarity that if winding 12 is then energized, the resultant torque which is exerted on the vane will tend to rotate the vane in a counter-clockwise direction, as viewed in Fig. 1.

Relays embodying my invention are particularly suitable for, although in no way limited to, use astrack relays in signaling systems for electric roads in which the track rails, in addition to being supplied with signaling current at one frequency, usually .60 cycles per second, also serve as the return conductor for the propulsion current which is generally of a lower frequency such, for example, as 25 cycles per second. When a relay is used as a track relay in a system of this type, the local winding is supplied with current of the same frequency as the signaling erates with adjustable front and back stops current from a transformer or other local source, while the control winding is connected with the track rails. Under some conditions, however, both windings of the relay may be supplied with current of either signaling frequency, orpropulsion frequency, or both. It is desirable that the relay should operate when current of signaling frequency is supplied to the windings, but that the relay should not respond to current of propulsion frequency flowing in the windings. In' order to obtain this desirable operation, I provide the relay with a fourth core 35 which also cooperates with the vane and which is included in the field of the winding 16. The core 35 is substantially C-shaped, and, as here shown, is supported on non-magnetizable blocks 17a) which it' is fastened by means of screws 19. The blocks 17, in turn, are mounted on top of the core 13, and are held in place by screws 18. The poles of the core 35 are located on opposite sides of the vane, preferably in such a position that one center line of each pole (the substantially vertical center line as viewed in Fig. 1) lies approximately on a radius of the vane; and each pole is provided with a ferrule 20 of copper or other electro-conducting material which partially encloses the pole face to produce a rota ing magnetic field when the wind ing 16 is supplied with alternating current. This rotating magnetic field exerts a second torque on the vane, and the parts are so arranged that this torque will act in the opposite direction'to and hence, will oppose, the main torque.

Furthermore, each leg of the core 35 is surrounded by a short-circuiting band 21, the function ofwhich will be made clear as the descriptionproceeds. It will also beno ed from an inspection of Fig. 2 that the air gap between the poles of the'core 35 is smaller than theair gap between the poles of the core 13. The reason for this will like wise be made clear hereinafter.

A contact carrying rocker arm 22 (see Fig. 1) is pivotally mounted at 23 in suitable housings not shown in the drawings, and is provided with a substantially horizontal arm 24 which is pivotally connected with the upper end of. a link 25.. The lower end of the link 25 is pivoted on a pin .26 which is movable with the vane 7. As here shown, this pin passes through a jaw 27 in an arm 27 which is attached to the shaft 6. The rocker 22 carries two contact fingers 28 and 29which cooperate with two fixed contacts 28 and 29, respectively, to close a contact 282S or 29-29 as will be explained hereinafter. The rocker'22 also carries a bar 31 and a counterweight 34. The bar 31 coop- 32 carried by a fixed block 33 to restrict the motion of the rocker 22 to the desired limits. The counterweight 34 serves to bias the rocker, andzhencethe vane, to a position inwhich the contact 28-28 is open and the contact 29-29 is closed, as shown in the drawings.

the windings 12 and 16 are-energized by currents of the signaling frequency (say 60 cycles) upon which the relay is intended to operate, the reaction pointed out hereinbefore between the fluxes set. up in the cores 8 and 9, due to the current in winding 12, and the flux set up in core 13, due to the current in winding 16,exerts atorque on theovane which tends to rotate the vane in a'counterclockwise direction. At the same time, a second or counter-torque is exerted on the vane by the rotating'inagnetic field set up by the flux in core 35. This counter-torque is small under these conditions however, because this torque is proportional to the strength of the flux in the core 35, and the. choking bands 21 on thiscore are so designed and the parts are soproportioned that atthe signaling frequency, the counter-flux set up in the core 35 due to the electromotive forces which are induced'in these bands will'force most of the flux due to Winding 16 through core 13. It will be apparent, therefore, that when both of the windings 12 and'16 are supplied with current of signaling frequency, the main torque will predominate and, as a result, the vane will rotate in-a counter-clock wise direction untilthe bar 31Vengages the lower stop .32, at which time further motion of the vane is prevented. Contact 2929 then become opened and contact 28-28 becomes closed; The parts will. then remain in these latter conditions until winding 16 is no longer supplied with the higher frequency current, at which time the parts will be returned to the positions shown by the bias of counterweight 34. V p

When windings 12 and 16 areenergiz'ed, by current of propulsion frequency (say 25 cycles) the choking effect of the short-circuiting bands 21 is considerably less than when current of the signaling: frequency is impressed on this winding and, since theair gap. between the poles of core35 is smaller than the air gap between the poles of core 13, most of the flux due to winding16 then passes through core 35; It follows that, at the propulsion frequency, the counter-torque due to core 35is very much larger than the countertorque at the higher frequency and, as a result, while at low encrgiz'ation of winding 16, there may still be a slight torque tending this torque will be insuflicient to overcome the bias of counterweight 34. As the voltage on winding 16 is raised, the counter-torque due to core 35 increases as the square of the ap plied voltage, while the main torque increases in direct ratio to the applied voltage. It will be apparent, therefore, that as the voltage in coil 16 at the propulsion frequency is raised, a point will be reached at which the counter-torque will completely balance the n'iain torque and, if the voltage is raised beyond this point, the counter-torque will even exceed the main torque. It follows that the relay will not respond to current of the propulsion frequency in its windings.

If current of both propulsion and signaling frequencies is supplied simultanmusly to the relay windings, the relay will operate to open contact 2929 and close contact E2828 in the manner previously described, provided the amount of the propulsion frequency current does not exceed a value which depends upon the proportioning of the parts (this-value being greater than that ordinarily encountered in actual practice). It the amount of the propulsion frequency current does exceed this value, however, the countertorque will become sufficiently large so that the vane will be held in the position in which contact 28-28 is open and contact 29-29 is closed.

It will be apparent from the foregoing that relays embodying my invention will re spond to energizing currents of a particular frequency but will not respond to currents of other frequencies. In this connection, it should be pointed out that the relay as here shown discriminates against currents of lower frequency than the signaling current, but this arrangement is not essential.

Although I have herein shown and described only one form of electrical relay bodying my invention, it is understood that various changes and modifications may he made therein within the scope of the appended claims Without departing from the spirit and scope of my invention Having thus described my invention, what I claim is:

1. A relay comprising a rotatable vmne, two operating windings, means responsive to alternating currents in said windings for passing through said vane fluxes which cooperate .to create a main torque on said vane which tends to rotate the vane in one direc tion, and means responsive to current in one said winding for creating a second torque which opposes said main torque and which is substantially equal to such main torque at one frequency of the current in said one winding but which is of lesser magnitude than such main torque at another frequency of such current.

2. A relay comprising a rotatable vane, means for inducing in said vane alternating currents, a winding, means operating when alternating current is supplied to said winding for passing a flux through said vane which reacts with said induced currents in said vane to create a main torque on said vane which tends to rotate said vane in one direction, and other means operating when alterna-ting current is supplied to said winding for applying to said vane a rotating magnetic field to produce a second torque which opposes said main torque and which equals said main torque at one frequency of the current supplied to said winding but which is of lesser magnitude than said main torque at another frequency of said current.

3. A relay comprising a rotatable vane, means for inducing in said vane alternating currents, a winding, means operating when alternating current is supplied to said winding for passing a flux through said vane which reacts with the induced currents in said vane to create a main torque on said vane which tends to rotate said vane in one direction, a core linking said winding and having two confronting poles separated by an air gap including said vane, a shading band partially enclosing the pole faces of at least one of said poles and operating when alternating current is supplied to said wind ing for applying to said vane, a second torque which opposes said main torque, and means associated with said core and operating when current is supplied to said winding for regulating the flux in said core in accordance with the frequency of the current in said winding.

4. A relay comprising a rotatable vane, means for inducing in said vane alternating currents, :a winding, means efi'ective when said wind-ing is supplied with alternating current for passing a flux through said vane which reacts with the induced currents in said vane to create a main torque on said vane which tends to rotate said vane in one direction, a core linking said winding and having two confronting poles separated by an air gap including said vane, a shading hand partially enclosing the pole face of at least one of said poles and effective when alternating current is supplied to said winding for applying to said vane a second torque which opposes said main torque, and means associated with said core and effective when current is supplied to said winding for regulating the flux in said core in such manner that said second torque is substantially equal to said main torque for one and only one frequency and magnitude of the current in winding,

5. A Delay comprising a rotatable vane, means for inducing in said vane alternating currents, a winding, means effective when alternating current is suppiied to said winding for passing a flux through said vane which reacts with the induced currents in said vane to create a main torque on said vane'which tends to rotate said vane in one direction, a core linking said winding and having two confronting poles separated by an air gap including said vane, a shading band associated with at least one of said poles and effective when alternating current is sup plied to said winding for applying to said vane a second torque which opposes said main torque, and means associated with said core and effective when current is suppliedto said winding for reducing the flux in said core as the frequency of the current in said winding lncreases. v

6. A relay comprising a rotatable vane, means for inducing in said vane alternating currents, a winding, alternating current is supplied to said winding for passing a flux through said vane which reacts with the induced currents in said vane to create a main torque on said vane which tends to rotate said vane in one direction, a core linking said winding and having two confronting poles separated by an air gap including said vane, a shading band associated with at least one of said poles and operating when alternating current'is supplied to said winding for applying to said vane a second torque which opposes said main torque, and at least one shortcircuiting band associated with said core for regulating the flux in said-core when currentis supplied to said winding in accordance with the frequency of the current in said winding.

7. A relay comprising a rotatable vane, means for inducing in said vane alternating currents, a winding, means effective when alternating currents are supplied to said winding for passing a flux through'said vane which reacts with the induced currents in said vane to create a main torque on said vane which tends to rotate said vane in one direction, a core linking said winding and having two confronting poles separated by an air gap including said vane, a shading band associated with at least one of said poles and effective when alternating current is supplied that said second torque is substantially equal 7 to said main torque for one and only one frequency and magnitude of the current in said winding.

8. A relay comprising a rotatable vane,

' means for inducing in said vane alternating currents, a winding, means operating when alternating current is supplied to said winding for passing a flux'through said vane which reacts with the induced currents in said vane to create a main torque on said vane which tends to rotate said vane in one means operating when:

direction, a core linking said winding and having two confronting poles separated by an air gap including said vane, a shading band associated with at least one of said poles and effective when current is supplied to said winding for applying to said vane a second torque which opposes said main torque, and at least one short-circuiting band associated with said core and operating when current is supplied to said winding for re ducing the flux in said core as the frequency of the current in said winding is increased.

9. A relay comprising a rotatable vane, a first core having two confronting poles separated by an air gap including said vane, a winding associated with said core for setting up alternating fluxes "in said core which thread said air gap, means for inducing in said vane alternating current's which react with the fluxes in said air gap to create a main torque on said vane which tends to rotate said vane in one'directi-on, a second core linking said winding and having two confronting poles separated by an air gap including said vane, a shading band'associated with at least one pole of said second core and effective when alternating current is supplied to said winding for applying to said vane a second torque which opposes said main torque, and means for regulating the strength of said second torque in accordance with the frequency of the current in said winding;-

10. A relay comprising a rotatable vane, a first core having two confronting poles separated by an air gap including said vane, a winding associated with said core for settin up alternating fluxes in said core whic 1 thread said air gap, means for inducing in said vane alternating currents which react with the fluxes in said air gap to create a main torque on said vane which tends to rotate said vane in one direction, a second core linking said winding and having two confronting poles separated by an air gap including said vane, a shading band associated with at least one pole of said second core and effective a when alternating current is supplied-to said winding for applying to said vane asecond torque which opposes said main torque, and

at least one short-circuiting band on said second core for regulating the flux in said second core in'accordance with the frequency of the current in said windin 11. A relay comprising a rotatable vane, a first core having two confronting poles separated by an air gap including said vane, a winding linking said core for setting up in said core alternating fluxes which thread said air gap,

means for inducing in said vane alternating currents which react with the fluxes which are createdin the air gap between the poles of said first cores to create a main torque on said vane which tends to rotate said vane in one direction, a second 'core linking said wlndmg and having two confronting poles separated by an air gap including said vane, a shading band surrounding a portion of at least one of the poles of said second core and effective when alternating currents are supplied to said winding for applying to said vane a second torque which opposes said main torque, and at least one short-circuiting band on said second core, said band and the air gaps between the poles of said cores being so proportioned that when alternating current at one frequency is supplied to said winding, most of the flux due to said winding will flow through said one core but that when alternating current at another frequency is supplied to said winding, most of the flux due to said winding will flow through said other core.

In testimony whereof I aflix my signature.

BERNARD E. OHAGAN. 

